If you are good at doing projects. Along the way you learn a lot of other very important life skills. Things like resourcefulness, persisting at things, immunity to failure, trying many times etc. And these come handy and are usable to to many things that actually matter in the real world. That is building things.
These things are harder to gain at a later stage in life because expectations from one's life at that time are different and you have to worry more about monthly payments and putting food on the table. You don't have 10 - 15 years lying around to do what other programmers have done in their early years where it was cheap to that in terms of time.
You are also discounting the accumulative effects of these things. After a while due to years of practice, early starters are likely to get very good at things in a far more disproportionate way than those who come later.